Effects of biochar addition on nitrous oxide emission during soil freeze–thaw cycles

Abstract

Biochar applied to soil can reduce nitrous oxide (N2O) emissions produced by freeze–thaw processes. Nonetheless, how biochar modification affects N2O emissions during freeze–thaw cycles is not completely clear. In our research, during freeze–thaw cycles, microcosm experiments were conducted to investigate the effects of maize straw biochar (MB) or rice straw biochar (RB) addition on soil N2O emissions under different water conditions. The N2O emissions peaked at the initial stage of thawing in all the soils, and the total N2O emissions were considerably greater in the flooded soils than in the nonflooded soils. Compared with the soils without biochar addition, RB and MB amendments inhibited N2O emissions by 69 and 67%, respectively. Moreover, after biochar addition, the abundance of AOB amoA genes decreased by 9–13%. Biochar addition significantly decreased the content of microbial biomass nitrogen (MBN) in flooded soil during thawing, which was significantly correlated with N2O emissions and nitrification and denitrification communities. The PLS-PM further revealed that biochar can inhibit the production and emission of soil N2O by reducing soil MBN during soil thawing. In addition, soil moisture directly significantly affects N2O emissions and indirectly affects N2O emissions through its influence on soil physicochemical properties. Our results revealed the important function of biochar in decreasing the emission of N2O in flooded soil during freeze–thaw cycles.

The Substitution of Sphagnum for Peat as a Culture Substrate Reduces N2O Emissions from Vegetable Production Systems

“…Redundancy analysis (Figure 5A) showed that environmental factors explained 82.4% of the variation of the denitrifying bacteria genera in this study, with C/N explaining most of the variation, followed by EC and NO 3 -N. This was similar to previous correlation analyses of soil properties with bacterial communities [38]. It can be concluded that sphagnum substitution significantly alters C/N, EC, and NO 3 − -N, which indirectly affect the variation in denitrifying bacteria genera communities, ultimately resulting in different N 2 O emissions [39]. Correlation heat map analysis (Figure 5B) showed that Rhodanobacter was positively correlated with C/N and EC and negatively correlated with the pH.…”

Biochar as a tool for the improvement of soil and environment

“…A previous study reported that the application of animal manure resulted in a 17.7% increase in N 2 O emissions, while the use of biochar amendments significantly reduced N 2 O emissions by 19.7% (Shakoor et al, 2021). In another experiment conducted in flooded and non-flooded soils during freeze-thaw cycles, the addition of biochar led to a noteworthy decrease in N 2 O emissions, with reductions of up to 67% (Yang et al, 2022b).…”

Differentiate responses of soil nutrient levels and enzymatic activities to freeze-thawing cycles in different layers of moss-dominated biocrusts in a temperate desert

“…There is growing evidence that these changes in FTC patterns can affect the soil ecosystem. FTCs alter soil structure ( Zhang et al., 2016 ; Zhang et al., 2021 ), water cycling ( Wang et al., 2021 ; Li et al., 2021b ), gas emission ( Hamamoto et al., 2020 ; Yang et al., 2022a ), and litter decomposition ( Pelster et al., 2013 ). Studies have also shown that FTCs affect microbial community structure and function ( Liu et al., 2021 ; Sang et al., 2021 ) and plant root dynamics ( Tierney et al., 2001 ; Sorensen et al., 2016 ).…”